Polish: Making Your Restorations Shine

Polishing a restoration creates a smooth surface that simulates the glossy look of the patient's enamel. As the final step, polishing serves as your last chance to optimize the success of the restoration. Therefore, we look at the advantages of polishing and the different materials suitable for various restorative goals.

There are quite a few advantages to finishing and polishing in addition to looking good. Polishing requires clinicians to smooth the cavosurface margins and reconstruct the functional anatomy of the restored tooth, providing an imperceptible restorative margin free from voids. The glossy surface of a polished restoration also creates a plaque-resistant environment for the patient, making it easier for them to clean and contributes to the excellent health of the patients' gingival tissues. These factors lead to increased longevity of the restoration.¹ 

In other words, polishing is the last step but a no less crucial one than all that came before it. If you skimp here, you could end up with poor implications for oral health, restorative function, and esthetics, which range from biomaterial accumulation, irritated gums, and surface staining.²

Clinicians polish right after contouring and finishing. It usually starts with pre-polish, where the dentist removes the scratches that might have occurred during finishing. Dentists then establish a smooth surface. Then, the clinician goes back to "super-polish" the restoration. This third step is where clinicians achieve the enamel-like luster that everyone wants.²

However, all resin composites do not produce the same surface roughness. Different variables affect this factor, some of which come from the materials themselves and some from external agents. Internal factors include the type of material and fillers and the fillers' shape, size, and distribution. Also, the polymerization, resin makeup, and bond durability between the filler and the matrix affect the success. The external factors originate in the clinician's finishing and polishing technique. These include the flexibility and shape of the polishing tools, which abrasive they use and its related hardness, and the clinician's polishing skill.³

Unlike the finishing phase, which establishes the restoration's form and texture, polishing is about getting the luster right, to the point that the patient doesn't notice the repair in their mouth. Practical Procedures in Aesthetic Dentistry suggests facilitating some "dark polymerization” by waiting 10-15 minutes after light curing to polish. In addition to general observation of the patient's other teeth and those related esthetics, they recommend tungsten carbide burs to develop the macro-texture and proximal burs for gingival and proximal finishing.⁴

Polishing Material Types Have Different Strengths and Uses

What you use to polish composite restorations has a lot to do with restoring the tooth. Jeff Lineberry, DDS, FAGD, AAACD uses different systems and pastes depending on what function the tooth surface will serve the patient best.

"It's a whole different ball game in the facial anterior surface than an occlusal area," Dr Lineberry agrees. "The wear and tear that you get on a facial surface are different than the occlusal surface, so it's not subject to the same conditions."

One of the most popular abrasive materials for direct and indirect restorative dentistry is diamond polishing paste. Studies suggest that these pastes are successful in decreasing biofilm accumulation and providing excellent surface properties for the restoration.^5,6

In her private practice in Newport Beach, CA, Sarah Jebreil, DDS, AAACD, likes to use diamond paste on the anterior restorations. Dr Lineberry uses it there but will sometimes use the diamond-impregnated paste on the posterior too. However, Dr Lineberry says that using diamond paste with a felt polisher in posterior restorations has more to do with feel than looks.

"It will take it to a level of polish that patients will say it feels like their tooth," Dr Lineberry explains.

Dr Jebreil says her posterior work is rarely a direct composite filling and is more likely to be an onlay or an inlay, which she polishes with regular polishing compound. 

"I like to use the points and cups. In the posterior, I finish it primarily with the finishing burs, my interproximal burs, and then working to the fine point balls bur polishers, and then go over it to polish it," Dr Jebreil explains. "When you do that, you see if the rubber cup is getting stuck in a void. Then, you can remove it and refinish it."

For a Class IV or a MIFL composite restoration, Dr Lineberry likes to use discs, from coarse to fine. Then, he will use a polish and buffer with a diamond enhanced paste.

However, in some cases, dentists can use a liquid polish. Some studies suggest liquid polish could help dentists achieve a perfect marginal seal. Applying a thick layer of a flowable resin with no filler to the cavosurface margins of the finished restoration can penetrate the micro defects and marginal gaps. The capillary action seals them and improves the marginal seal. One study suggests that the resin could also repair the pores and structural defects that occur during finishing and polishing.⁷ 

In Dr Jebreil's experience, she doesn't like to use lacquer unless it's on a provisional. While she likes how liquid polish can seal porous acrylic materials, it wears away and stains over time. Liquid varnish also doesn't allow clinicians to fix voids when they should. Furthermore, if you put lacquer on a gap rather than repairing it, the lacquer will wear away, and the rough patches underneath will still be there. Then, the restoration gets bacteria in it, which can lead to recurrent caries. Also, restorations can have pits that look black as they age, which she wants to avoid.

"It's like the filling has a cavity in it, and it's because the restoration wasn't finished and polished properly," Dr Jebreil says. "For the long-term, you are better off polishing the restoration."

"As much as we would love to have a clear coat polish in the mouth like they put on cars, we don't have anything like that. Ultimately, that clear coating wears away. If you have a polished surface, then you have it, and it's not going to change," Dr Lineberry agrees. "I love clear sealers for provisionals. It works great for the final finish on provisionals."

What Dentists Should Remember about Polishing

Dr Jebreil thinks that clinicians should try many different polishing systems to find the one that works best in their hands. She likes the white cups and the pink and white cups. She also likes the goat hair polishing brushes because they make less of a mess and work well in her hands. 

"But maybe someone else likes something different. So, there are so many different products out there. Try a couple of different things and see what works, and you can mix and match, too, like 1 coarse from 1 company and 1 fine from another company," Dr Jebreil says. "You have to make your own formula." 

Dr Lineberry thinks clinicians should remember that polishing sets the stage for a longer-lasting restoration. When dentists polish away that flash, they reduce surface stains and discoloration. They also reduce plaque accumulation around those rough areas.

"It's worth the steps. Take the time and polish," Dr Lineberry says. "Your composite resin restorations will survive longer and look better if you do your proper finishing or polishing upfront."

References

1. Walls AT. Composite finishing and polishing. Pocket Dentistry. Published February 11, 2020. Accessed November 5, 2021. https://pocketdentistry.com/composite-finishing-and-polishing/

2. Koirala, Sushil. (2020). Direct Composite Resin Finishing & Polishing Technique. 1. 18-22. Published August 2020. Accessed October 25, 2021. https://www.researchgate.net/publication/343629191_Direct_Composite_Resin_Finishing_Polishing_Technique 

3. Silva JP, Coelho A, Paula A, et al. The Influence of Irrigation during the Finishing and Polishing of Composite Resin Restorations—A Systematic Review of In Vitro Studies. mdpi.com. Published March 29, 2021. Accessed October 25, 2021. Materials-14-01675.pdf. 

4. Banerji, S. and Mehta, S.B. (2017). The Finishing and Polishing of Resin Composite Restorations. In Practical Procedures in Aesthetic Dentistry (eds S. Banerji, S.B. Mehta and C.C. Ho). https://doi.org/10.1002/9781119324911.ch5.6

5. Kurt A, Cilingir A, Bilmenoglu C, Topcuoglu N, Kulekci G. Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation. J Dent. 2019;90:103199. doi:10.1016/j.jdent.2019.103199

6. Chour RG, Moda A, Arora A, Arafath MY, Shetty VK, Rishal Y. Comparative evaluation of effect of different polishing systems on surface roughness of composite resin: An in vitro study. J Int Soc Prev Community Dent. 2016;6(Suppl 2):S166-S170. doi:10.4103/2231-0762.189761

7. URQUÍA, M. C.; BRASCA, N.; GIRARDI, M.; BONNIN, C.; RÍOS, A.; GIRARDI, I.; CHÁVEZ, L. J. & DELGADO, A. Influence of surface sealants on microleakage in composite restorations. Int. J. Odontostomat., 11(4)